## 1.5. Guide for Users of BSD-Derived Systems

Those of you making a transition to SVR4 from a BSD-derived system should note that BSD commands reside in your system's `/usr/ucb` directory. This is especially important when using certain commands, because the compatibility packages include several commands that have an existing counterpart in SVR4, and the two versions usually work differently. If your PATH variable specifies `/usr/ucb` before the SVR4 command directories (e.g., `/usr/bin`), you'll end up running the BSD version of the command. Check your PATH variable (use `echo $PATH`) to make sure you get what you want. The commands that have both BSD and SVR4 variants are:

`basename` | `du` | `ls` | `tr`
`cc` | `echo` | `ps` | `vacation`
`chown` | `groups` | `stty` |
`deroff` | `ld` | `sum` |
`df` | `ln` | `test` |

This book describes the SVR4 version of these commands. (Often, the standard Solaris version of a command includes features or options from the BSD version as well.)

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